Conway Groups
The Automorphism Group 
of the Leech Lattice modulo a center of order two is called ``the''Conway group. There are 15 exceptional Conjugacy Classes of the Conway group. This group,combined with the Groups 
and 
obtained similarly from the Leech Lattice bystabilization of the 1-D and 2-D sublattices, are collectively called Conway groups. The Conway groups areSporadic Groups.
References
Wilson, R. A. ``ATLAS of Finite Group Representation.''http://for.mat.bham.ac.uk/atlas/html/contents.html#spo.
- Node (Fixed Point)
- Node (Graph)
- Noetherian Module
- Noetherian Ring
- Noether-Lasker Theorem
- Noether's Fundamental Theorem
- Noether's Transformation Theorem
- Noise
- Noise Sphere
- Nolid
- Nome
- n-Omino
- Nomogram
- Nonagon
- Nonagonal Number
- Nonagram
- Nonassociative Algebra
- Nonassociative Product
- Nonaveraging Sequence
- Noncentral Distribution
- Noncommutative Group
- Nonconformal Mapping
- Nonconstructive Proof
- Noncototient
- Noncylindrical Ruled Surface